Various kinds of filter constructions have been long used for removal of offensive odors. One of the long used filters employ activated carbon in conjunction with a particulate filter media and has enjoyed a limited degree of success for odor reduction in certain applications.
In particular applications, such as filters used in connection with enclosed litter boxes for cats a filter media pad has been used employing zeolite to attempt to more effectively remove pet odors emanating from the litter box. Zeolite is naturally occuring minerals also known by a variety of names including chabazite and clinoptilolite for example. However, this mineral is known to have particular effectiveness in adsorbing gaseous ammonia compounds, such as associated with urine odors, and therefore is helpful to use in such applications such as pet litter boxes or in aquariums.
Prior to the present invention a highly efficient yet relatively inexpensive filter for such pet applications has not been proposed or developed by the trade.